Modal dialog to modeless dialog

Question

Hi

I have a modal dialog and it is up and running. Now, on one of the dialog button click, I want to activate a command that need me to select something out of the dialog (i.e. expecting it to be modeless now). Can I achieve the same? This is for QT in C++.

In short, once dialog set as modal and displayed, can I make it modeless for a moment on dialog button click?